Several researchers have hypothesized that the visual analysis of human movement differs fundamentally from other motion analyses. However, to date, no studies have systematically examined how the perception of human movement differs from the perception of other complex motions. As a result, the mechanism underlying the visual perception of human movement remains largely unknown. To resolve this issue, three converging lines of investigation are proposed. The goal of the first series of psychophysical experiments is to systematically define the visual system's sensitivity to human movement. In the second investigative approach, visual sensitivity to human movement will be compared with visual sensitivity to other complex motions. Only once these two data sets have been collected can one directly test whether the visual analysis of human movement truly differs from other motion analyses. The goal of the final line of investigation is to ascertain whether the visual analysis of human movement depends upon motor experience. That is, do we visually interpret the movements of others in terms of our own motor system? Or, is the visual analysis of human movement dependent upon extensive visual exposure to this movement? The results of these experiments will allow us to construct, for the very first time, a comprehensive model of the visual analysis of human movement. Such a model will have significant implications for our understanding of the interaction between the motor and visual systems. Moreover, these results will challenge current theories of processing specialization and, as a result, assist in the diagnosis and treatment of patients with localized lesions in late visual areas.